Many types of communication techniques and protocols have been developed over the years. One example is the wireless cellular telephone network. The cellular network relies upon digital or analog telecommunication signals in which a subscriber is wirelessly connected from a mobile telephone to a nearby transmitter. The transmitter's span of intended coverage is called a cell. Cellular telephone service is available in many diverse geographic areas, such as urban areas and along major highways. As the cellular telephone user moves from one cell or area of coverage to another, the telephone is effectively passed on to the local cell transmitter. Certain types of telephone services, such as Code Division Multiple Access (CDMA), may require the use of personalized plug-ins, called CDMA Subscriber Identity Module cards (CSIM cards). These CSIM cards are inserted into cellular telephone handsets that contain security codes and personal information specific to the service level, and individual preferences and data stored by the individual. A user can swap a CSIM card, so a new device need not be registered on the cellular network when a handset is replaced. For purposes of brevity, the term CSIM can refer to a CSIM card and any other memory device or module that stores information.
A CSIM stores an identification number of a home network and a subscriber within the home network which collectively can be called an international mobile subscriber identity (IMSI). The CSIM may optionally store other information about a user such as the user's name, telephone number, address book, and other identifying features. The CSIM may be an electronic memory device or other means for storing information. It may be mounted in a communication device or coupled to the communication device by a wired or wireless communication link. For example, a CSIM may be a thin card that is carried with a mobile telephone under a battery or behind a battery door.
The IMSI is a unique, non-dialable number allocated to each mobile subscriber that identifies the subscriber and his or her operator subscription. The IMSI is stored in the CSIM. The IMSI is made up of three parts: 1) the mobile country code (MCC) consisting of three digits, 2) the Mobile Network Code (MNC) consisting of two digits, and 3) the Mobile Subscriber Identity Number (MSIN) consisting of up to 10 digits.
A Home Location Register (HLR) is a database that contains mobile subscriber information for all subscribers. A Visitor Location Register (VLR) is a database owned and maintained by a mobile operator. It contains temporary information about mobile subscribers that are currently located in a geographic area serviced by that mobile operator, but whose Home Location Register (HLR) is elsewhere.
HLR subscriber information includes the IMSI, service subscription information, location information, service restrictions, and supplementary services information. The HLR also initiates transactions with the VLR to complete incoming calls and to update subscriber data.
A Universal Integrated Circuit Card (UICC) is a smart card used in mobile terminals in Global Systems for Mobile Communications (GSM) and Universal Mobile Telecommunications System (UMTS) networks. The UICC ensures the integrity and security of multiple kinds of personal data. In a GSM network the UICC contains a SIM network application. In a UMTS network, the UICC contains a USIM network application. A UICC may contain several network applications, making it possible for the same smart card to give access to both GSM and UMTS networks, and also provide storage for a phone book and other applications. It is also possible to access a GSM network using a USIM network application, and it is possible to access UMTS networks using a SIM network application with mobile terminals prepared for this type of communication.
In a CDMA network, the UICC contains a CSIM network application, in addition to 3GPP USIM and SIM applications. A card with all three features is called a removable user identity card (R-UIM). Thus the R-UIM card can be inserted into CDMA, GSM, or UMTS handsets and will work in all three cases.
The UICC smart card consists of a CPU, ROM, RAM, EEPROM and I/O circuits. Early versions consisted of the full-size (85×54 mm, ISO/IEC 7810 ID-1) smart card. The development of smaller and lighter telephones, with a smaller form factor and decreased internal real estate, called for a smaller version of the card. In some of the newer phones, the UICC card was cropped down to 25×15 mm (ISO/IEC 7810 ID-000). There may be further changes to smart card design, depending upon the design of the phone, or other mobile devices that these cards may support.
Since the card slot is standardized, a subscriber can easily move their wireless account and phone number from one handset to another. This will also transfer their phone book and text messages. Similarly, a subscriber can usually change carriers by inserting a new carrier's UICC card into their existing handset. However, it is not always possible because some carriers in certain countries (e.g., in U.S.) SIM-lock the phones that they sell, thereby preventing rival carriers' cards from being used in their phones.
The use and content of the card can be protected by use of PIN codes. One code, PIN1, can be defined to control normal use of the phone. Another code, PIN2, can be set, to allow the use of special functions (like limiting outbound telephone calls to a list of numbers). PUK1 and PUK2 are used to reset PIN1 and PIN2, respectively.
Other possible applications on a UICC smart card include Intelligent SIM (ISIM), to secure mobile access to IP multimedia services, and non-telecom applications such as payment. For example, many subscribers have a UICC with USIM and ISIM applications for phone service and multimedia respectively.
CSIM may also be an application on a universal integrated circuit card (UICC). After activation of a CSIM application on a UICC, the card triggers a refresh procedure asking the mobile equipment (ME) to read a set of files that may have changed during the activation process in order to update the ME's copy of those files. During normal operation, the refresh procedure triggered by the card should not cause a dropped voice or data call. The trigger for the refresh may also be carried out by the ME in order to update its activation and user files.
In order to implement this logic, when a proactive command with a refresh command/message is received from the UICC card, the ME polls its internal services via a voting mechanism to determine if a refresh can be carried out. In the case where one or more of internal service votes are received against the refresh, the request is rejected. After card activation, the ME may have an active data call, causing the refresh to be postponed. This might happen for several attempts that are initiated by the card. This may result in a long delay, before the actual refresh takes place.
As a result, the newly-programmed mobile identification number-based IMSI (IMSI_M) value is not available to the ME. The unavailability of the IMSI_M makes the ME unable to perform a voice call over a CDMA network and typically shows an “Emergency calls only” message on the screen to the user. This might be interpreted as a malfunctioning device, even if every module is working in accordance with the original design and expected operation. This and other features of the refresh procedure are described throughout the present specification and more particularly below. It is therefore desirable to have a solution that can overcome voting mechanism latency for faster, more accessible refresh options.